Storage type electron tube systems



April 8, 1958 P. T. FARNSWORTH 2, 1

STORAGE TYPE ELECTRON TUBE SYSTEMS 4 Sheets-sheaf 1 Filed Oct. 6;"1951 OUT - INVENTOR B 71 FARNSWORTH DISPLAY /5c2 GREEN I BLUE RECEIVER ATTORNEY April 8, 1958 -P. T. FARNSWORTH 2,830,111

STORAGE TYPE ELECTRON TUBE SYSTEMS Filed Oct. 6, 1951 4 Sheets-Sheet 2 FIG. 3.

R I! FARNSWOR TH ATTORNEY April 8, 1958 P. 'r. FARNSWORTH STORAGE TYPE ELECTRON TUBE SYSTEMS 4 Sheets-Sheet 3 Filed 001;. e, 1951 INVENTOR P. T, mzvswolez'u BY ATTORNEY April 8, 1958 P. 1-. FARNSWORTH 2,330,111

I STORAGE TYPE ELECTRON TUBE SYSTEMS.

4 Sheets-Sheet 4 Filed Oct. 6, 1951 FIGQT.

- INVENTOR B T FARNSWflRT ATTORNEY 2,830,111 r STORAGE TYPE ELECTRON TUBE SYSTEMS Philo T. Farnsworth,Fort Wayne, Ind, assignor to International Telephone and Telegraph Corporation, a cor This invention relates to storage type electron tube systems and methods using electron storage, or memory tubes, and more particularly tube systems applicable to color television.

A storage tube and image production tube system has been proposed wherein there is provided a storagescreen which stores charges representative of an image signal. This screen with the storage image signal then serves to control the flow of electrons so that upon the later scanning of the electrode by an electron beam, an image of the stored signal maybe produced. An example of a particular type of storage' tube and certain circuits therefor, is illustrated in a prior application of the present inventor, Serial No. 197,612, filed November 25, 1950.

Broadly speaking, the invention provides storage means into which the information corresponding to different aspects of a common pattern (as, e. g., the information referring to the three colors of a picture) is written. A separate storage area is provided for each aspect; these areas may lie within one tube envelope or in separate tubes. The information may be readout in the form of electrical signals, and the repetition rate at which they are read out may be different from that at which the information originally was written into the storage device. These read-out signals may be applied to as many control electrodes as there are aspects. These control electrodes either belong to separate picture reproducing tubes (with optical means to superimpose the diiferent color signals), .orare comprised in a single tube of the variety commonly called a three color tube. Alternatively, the information may be continuously read out as an electron stream in the same tube which contains the storage means, this electron stream producing a visible image or a plurality of visible images, the

latter ones again forming the final patternby optical superposition. Y f

The invention may beregarded as a picture or picture element sequential transmission system in which pictures or separate picture aspects are transmitted for reproduction at a low repetition. rate but at a rate sufficiently high so that the still or non-moving components of the picture will besuccessfully reproduced without flicker and will have a high degree of definition and will suffer no loss of color. The moving components of the picture will also be reproduced without flicker but with somewhat less detail definition. The picture components representing movements at speeds below or substantially at the scanning repetitionrate will have substan- .tially the same detail definition as the still pictures but those moving at a high speed will have decreasingly de- A graded definition of picture elements and color dependent upon the-speed of movement. However, in actual direct viewing of moving objects, those objects moving at a relatively high speed do not present a clear definition to the eye as do stationaryobjects and therefor there will be substantially no noticeable'loss of detail in the overall picturereproduced, I

For the purpose of obtaining effective signals repre- Uni e States Patent sentative ofeach of several Z,830,l 1 1 Patented Apr. 8, 1?5

2 age signal aspects, which may be the separate color field imagesof a color television picture (or any other three elements into which a colored image may be resolved), separate stereoscopic image signals, or the like, applicant utilizes storage tubes which are of a similar type to those described above.

It is an object of this invention to provide a method and system wherein separate image field patterns repre-r sentativeof different aspects of the same signal, for example, separate color fields of a picture, are successively each of the stored image field patterns are simultaneously and continuously read out of or controlled by the storage means at a rate higher than said predetermined rate, or continuously reproduced, under control of the stored I energy. For example, the individual separate storage storage means.

meansmay be read out a plurality of times for-e'ach' application of storage signals to the device and these read-out signals may be applied to a utilization device, which may be used as an image control or-a system directly to produce visual images.

In accordance with a feature of this invention, two or more image signals representing the color field of a color picture signal, a stereoscopic picture, or other aspects of an image, are successively stored on separate This storage meansmay comprise a dielectric sheet or mesh screen in a single tube,,or separate storage screens in individual tubes. The image signals representative of each stored field are read 01f at the -same speed at which they are applied, for'example,

taneously read out a plurality of times correspondingto the number of ,fields to be separated, whereby the read ing rate is substantially amultiple of the average storage rate. The output signals may be appliedto an output circuit coupled to a collector plate or separate plates, and these separate outputs may be used to control reproduction of a color picture by means of separate color reproduction tubes. An image from each tube maybe superimposed in register to reproduce the picture. Alternatively, ,the signal outputs may be applied to a specially built tube which serves on a single screen to reproduce separator color picture patterns in suitably inter-leaved relation as, for example, the proposed .three gun color tube. Neither of these types ofcolor-repro- .duction form part of the present invention and so have been illustrated only diagrammatically. The systems in accordance with this invention may operate on'the principle of sequential color field scanning or sequential color element or like reproduction type systems. 1

Each of the color field signals as read out may be used to vary separate tubes with individual luminescent 5 image.

screens which are color segregated by light filters or by phosphors which luminesce at different colors to produce separate color field light images. These different patterns may then be superimposed to provide the composite color where sequential field reproduction is used.

According to a further feature of this invention, there may be provided a single cathode ray tube provided C with a perforate storage screen. A first electron gun source may be directed toward. the screen and su'ccessively scanned over separate areas, while the different color component signals are applied to cause electrostatic charges on the separate areas of the mosaic representing the different color images. A source of electrons, Which may be termed a flood gun, serves to provide an effective electron cloud, orvirtual cathode, adjacent the charged surfaces. Positively polarized electrodes, arranged on the other side of the screen attract electrons from the virtual cathodethrough the perforations in the screen to produce electron images of the separate color components. In

This system may be preferable in some cases one embodiment of the invention the electron images may be focussed on separated unitary areas of luminescent material to provide the separate color images. The areas may be of phosphors which provide the separate colors or may be provided with color filters to produce the separate color image components. The three color images may be superposed by optical means to provide the completed picture.

In another embodiment of the invention, the three electron images may be focussed through a perforate screen from different angles so that each image covers the entire viewing screen. Because of the perforations and the angles of travel of the separate electrons of the electron images, theelectrons will impinge on the viewing screen at different intermixed points. At each of the points the corresponding color phosphors or filter units are deposited. Thus, the viewing screen presents an effective superposition of the several color component images.

Itwill be evident that the methods and system of this invention are flexible and are, therefore, applicable alike, to different scanning speeds as well as to different transmission systems. In view of the fact that the separate color images are stored and that the reproduction of images may take place at a relatively high rate, the basic sequential scanning rate for individual pictures may be made considerably lower than present standards without deterioration in the definition or brilliance of the reproduced picture.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagrammatic representation partly in section of one type of storage tube suitable for use in the system of this invention;

Fig. 2 is a diagrammatic circuit showing a system applying the principles of this invention;

Fig. 3 is a diagrammatic illustration of a further embodiment of this invention, partly in section and partly in schematieform;

Figs. 4 and 5 are a sectional view and an exploded view, respectively, more fully illustrating the cathode gun assembly of Fig. 3;

Fig. 6 is a view, partly in section, of a further modification of a direct viewing tube incorporating the features of this invention;

Figure 7 is a sectional view taken along lines '7--7 of Fig. 6, and

Figs. 8 and 9 are diagrammatic views illustrating in greater detail the operation of the system illustrated in Fig. 6.

Turning first to Fig. 1, there is shown a type of memory or storage tube having an. envelope 1 and provided with two electron gun arrangements 2 and 3, near one end thereof. At the other end is provided a storage screen or electrode 4. Horizontal and vertical scanning windings are shown at 5 and 6 respectively, together with a focussing winding 7. Storage screen 4 comprises an insulating layer 8 mounted on a backing plate electrode 9. A collector electrode 10 is mounted within said tube intermediate the storage screen 4 and the electron guns 2 and 3. Electron gun 2 may comprise a cathode 11, a grid or concentrating electrode 12 and an accelerating elec trode 13. Electron gun 3 may comprise a similar cathode 14, a control electrode 15 and an accelerating electrode 16. A common dropping resistor orpotentiometer 17 coupled at one end to a source of negative potential, and at the other end to a source of positive potential may be provided to furnish the desired operating potentials for the electrodes of guns 2 and 3, the storage screen 4 and collector electrode 10.

In operation the image signal may be applied over cou- 4 pling condenser 18 to grid 15 of gun 3. The cathode of gun 3 is preferably sufliciently negative with respect to backing plate electrode 9 so that the electrons emitted J therefrom will bombard the insulating storage surface.

The velocity of the beam from gun 3 may be sufficient to cause secondary emission in which case the image signal will produce a positive charge storage pattern on the aperture screen or it maybe made of such velocity that less than unity secondary emission occurs, in which case a negative charge image storage is provided. Collector electrode 10 serves to withdraw the secondary electrons emitted. It will thus be seen that the electron gun 3 may be considered as the writing gun which serves to impress the image signal pattern onto the storage screen. Gun 2 may be considered as the reading gun and in scanning over the surface of the storage element 8 will serve to produce potentials corresponding to the stored image signals across output resistor 19 so that the output signals will appear at output terminal 20. The output apertures of both guns are focussed on the surface 8. The focus distance d is given by the following formula:

where K is a constant, B is the potential difference through which the electrons fall, and H is the magnetic field strength. In the present instance the condition that both beams are focussed can be fulfilled even though H .is the same for both beams. This is true because the distance d and the voltage E is different from the beams from each of the guns, for example, d1 for gun 3 and d2 for gun 2; and E1 for gun 3 and E2 for gun 2. The proper focussing of the two beams on the same surface may be obtained by assuring the following relationship between the two:

/E1 /Z d1 T d2 Additional flexibility may be obtained by providing separate focussing coils so that the focussing field strengths are different to the left and right of gun 2.

The operating conditions for the tube are preferably such that the electrons from gun 2 barely reach the insulator coating 8 but return toward ring 10 which acts as a collector. The electrons from gun 3 then will be able to reach the insulator and charge it positively or negatively depending on the negative voltage of gun 3 with respect to gun 2. The electrons from gun 2 will then be able to come closer to the insulator 8 where the charge is relatively positive but will not approach so closely where the charge is more highly negative. Due to its potential with respect to the various electrodes the backing plate 9 will be able to sense the degree of approach of electrons from gun 2 so that the signal in the output resistor will vary during the scanning of the beam from gun 2 in accordance with the pattern impressed upon plate 8 by gun 3. It will be appreciated that in this manner reading ofi? of the signal may be had without producing an appreciable discharge of the storage pattern on surface 8. Thus the storage signal may be read a number of times. Accordingly by applying proper keying signals to gun 3 the image signals may be stored on surface 8 and then gun 3 disabled, while gun 2 continues to operate making successive readings of the stored image. The discharge rate from surface 8 may be made relatively sluggish so that between each reading only a relatively small decay of a few percent occurs. It Will also be apparent that a high degree of linearity in scanning is not important because the same scanning fields act on both the reading and writing beams.

One manner in which storage tubes of the type shown in Fig. 1 may be used for a reproduction of different components of a common signal is shown'iri the circuit arrangement of Fig. 2. The common signals may be,'

tubes 25, 26 and 27. Each of these tubes is likewise provided with reading guns 2' and with the horizontal andvertical scanning coils 5 and 6. Couplers22, 23 and 24 serve as gates controlled in accordance with 'the normal color switching signals so as to be operative only during the time when the respective color field ,signalsare being received. To this end there is provided a synchronizing signal separator 28 which serves to apply the color switching signals to a color switching device 29, which in turn applies a switching signal to gate couplers '22, 23 and 24 in sequence. The output from synchronizing signal separator 28 is also applied to control the horizontal and vertical sweep circuits 30 I and 31'respective1y, which in turn are coupled to the respective sweep coils 5 and 6 of tubes 25, 26 and Y27.

In operationit will be noted that during the writing interval the first color field, which may, for example, be the red, is applied through coupler 22 to tube 25 resulting in a storage of the red image signal pattern on the storagescreen of this tube. Simultaneously the reading beam will operate to produce the first output control pattern in output line '32. It will be noted that the reading beams intubes26 and 27 are simultaneously scanned but, liIlVlW of thefact that storage has, not yet occurred on these tubes, there would be ,no output signal. Since couplers 23 and 24 are not opened by the first or red signal pattern nowriting occurs on' these tubes. .When the next color field pattern, for example 'blue, arrives coupler 23 will be opened while 22 and 24 a renow blockedp As a consequence this second .or blue field signalv will be stored on tube 26 and the first read-ontsignal will occur at 33. Simultaneously the red will again be read out and appear on output line 32.

, When the third, or green, color signals are applied, gates 22 and .23 are closed while gate coupler 24 is opened so that the green signals will be stored on 27, producing the output pattern ,onoutput line 34. Simultaneously the output pattern of the red andblue will be again read out on their respective lines 32 and 33.- The sequence of color signal presentation will.then be repeated in the same mannerYthrough tubes 25, 26 and 27; It will thus be seen that each off-the. color field patterns will be separately stored once each three times but the signal pattern will be read out simultaneously and continuously from each of the tubes so that there will be three readings out of the signalfor each storage thereof. From 6 this it will be apparent that if a total frequency of twenty complete coldrfrarnes per second is used, there will still be a reproduction of each color raster at a fre- 25, 26 and 27 so that the pictures may be properly re-* 76 this type ofsystem the rt-hreeleolor guns :may be operated simultaneously :andrepeatedly in the same manner as would occur for the separate display tubes.

The circuit arrangement of Fig. 2 requires three separate storage tubes for the operation of a color television system. It should be understood that the elements of the three tubes may be combined in one envelope, if desired, for example'similar 1Z0 l.h6 embodiment shown in Fig. 3.

Turning now to Fig. '3 there is illustrated .schematically a circuit in accordance with another embodiment of my invention wherein energy may be received :from color field signals transmitted at .a predetermined rate and each received field may be reproduced an equal number of times or substantiallycontinuouslyduring the entire time of reception of all of these color fields. Although the invention is not so limited, the illustration is made of a circuit for using three color separation images .and optical means for superimposing these images to produce the final picture.

There is shown a special tube having an envelope 40 p and having at one end thereof a cathode ray gun struccolor deposits 45, 46 and '47, upon which ture 41, providing effectively a double cathoderay gun assembly and a storage mesh screen 42 toward which electrons from gunA-l are directed. A second screen 43 may be provided intermediatefithe storage screen 42 and the gun for the purpose of stabilizing the electron field adjacent the mesh screen. Electrostatic accelerating and collecting electrodes 44 and 44A may-be provided on the far side of the screen 41 and on the end of envelope are shown three "separate electron responsive the color separation images may be formed. 1

Electron gun assembly 41 may comprise a firstcathode .48, three control electrodes'49, 50, and 51, a -plate52 provided with three apertures '53, 54 and 55 aligned with openings in control electrodes 49, 50 and 51, andan ac celerating electrode 56. It will be seen that by use of this construction. three separate scanning beams are proproduced on the three separate screens. If desired, separate sweep circuits may be used for these tubes synchronized from the same synchronizing signals from separator 28 but more carefully controlled as to linearity thansweep circuits 30 and 31. p

Instead of utilizing the three separate tubesas at 36, 37 and 38 these blocks may represent the three separate color guns of a known type of color receiver tube in which vided for association with theseparate color deposits 45, 46 and 47. Horizontal scanningcoil 56 and vertical scanning coil 57 are provided to effect a scanning-movement of the beams from gun assembly 41. Plate 52 is coated with electron emissive material 58 andsuitably heated to provide a flood cathode emission servingas a flood gun. The accelerating electrode 56 serves to accelerate electrons emitted from surface cathode 52 toward the screen 42. Focussing control coils 59 and 60 are shown connected to adjustable focussing control source-61. so asJto control the focussing of the various electronemissions at the desired-points. Y a i we Operation of the system as disclosed in Fig. 3 maybe as follows: The energy comprising the three color components of the picture is received and detected on a receiver 62. The video output of .the receiver is applied over coupling condenser 63 to cathode electrode 48 of gun 41. j The synchronizing signal separator 64 serves to separate out the color switching signals and apply them to the color switching circuit 65 and to separate the horizontal and vertical synchronizing signals and apply them to the horizontal and vertical sweep circuits 66vand 67 respectively. The sweep voltages may be in the normal saw tooth form as indicated at 68' and 69; The-color switching signal is applied successively to the three sepa* rate control electrodes 49, 50 and 51 as indicatedto permit beams from apertures 53, 54, and 55 to be successively effective.

Each of the color switching wave pulses is made of sufficient duration to last throughout the scanning interval during the respective frame-intervals so that each cornplete color separation picture is stored, as a separate electrostatic image. The cathode emitting surface material 58 of gun 41 produces a flood electron beam which is scanned over the entire surface of 42 during the separate :color frame scaunings, so that electrons from this source are continuously present in the field between storage screen 42 and stabilizing screen 43 producing therein an effective virtual cathode or electron cloud. It will be understood that this scanning of the flood beam is not necessary to operation but may serve to provide a more uniform distribution of electrons, than a stationary flood ..beam. The electrons from this virtual cathode are at- .tracted through perforations in screen 42 by electrodes 44 and .44A .so that there is produced on the far side of storage. screen 412 electron images corresponding to the separate color field'patterns. .The focussing coil 60 serves to focus thezseparate' color patterns-onto the luminescent deposits-45, 46 and 47. ,These deposits may constitute phosphors which will luminesce in the respective colors or may consist of phosphors which would luminesce as white light with suitable color filters to provide the separate color images. These separate color images may then be .projected by an optical system, indicated by lenses 70, 71 and 72-and prisms '73 and 74 onto a viewing screen 75 in proper registration to produce the complete color picture.

It will be clear that if control voltages such as are provided by the system of Figs. 1 and 2 are desired, the flood cathode surface 48 may be replaced by three separate reading guns, and conductive pick-up plates used .to replace the color phosphors of 45, 46 and 47.

A better understanding of the cathode gun arrangement as used in Fig. 3 may be had by reference to the diagrammatic showing made in Figs. 4 and 5. The cathode 48 of gun 41 may comprise an indirectly heated emitter heated by filament 76, the emitted energy of which is passed through respective perforations 77, 78, 79 of control electrodes 49, 50, 51. are of very small cross-sectional areas so as to provide beams of elemental size. Cathode 48 is preferably pro- .vided with an elongated emitting surface 48a suflicient to provide emission over the areas of control electrodes 49, 50 and 51. The plate 52may be in the form of a hollow disc with a heater filament 80 therein, the openings 81, 82 and 83 being in the form of transverse perforations in register with the control electrode perforations 77, 78 and 79. A shell extension 84 may be maintained at a suitable potential as indicated and serves to shield the beams passing through the apertures. The accelerating electrode 56 may comprise a member maintained at a positive potential so that the electrons of the beams and of thefloor emitter will be accelerated at the desired speed toward the storage screen.

It will be clear that, while a particular gun assembly of the scanning beam gun and flood beam is shown, many other forms of gun assembly may be used. It is merely necessary that the scanning guns be synchronized with the transmitted picture scanning, and that the flood gun supply sufiicient electron concentration to provide continuous or repeated reproduction. Accordingly, the flood gun may be arranged so that it covers the entire mesh screen without deflection. Alternatively, the flood gun may be arranged to scan each color separation storage screen simultaneously with, or at a higher scanning rate than each frame scan of the scanning beam.

It will be apparent that the single tube embodiment has a number of decided advantages over the embodiment utilizing three separate tubes. It will be clear that although the illustrations have omitted certain control elements for the sake of simplicity, there will be required some type of amplitude control and zero adjustment equipment for the vertical and horizontal deflection systems of each of the three tubes in a three tube system. Furthermore, there are three separate. scanning-rays and all of Apertures 77, 78 and 79 manner as described in connection with Fig. 3.

the separate potential supply elements and the like must be duplicated to take care of the operation of such tubes. In utilizing the single tube embodiment, only one set of deflection means is required so that the number of controls used therewith is greatly reduced. In addition, since a single control potential supply is provided, there will not be the necessity of separate adjustments otherwise required to assure proper coordination of the various tube operations in this respect. Moreover, there is not the difficulty of checking separate emission and other tube characteristics to see that proper matching of the tubes is present and the problem of proper registry of pictures is greatly simplified. Since the single tube embodiment has the separate picture reproducing elements mechanically fixed with respect one to another, therev can be no loss of registry of the picture due to mechanical displacement of the picture screens as can easily occur where three separate tubes are used. It is, therefore, clear that the service problems as well as the cost of component parts are greatly reduced in systems utilizing the single tube arrangement compared with those systems utilizing scribed in connection with Figs. 1 through 5, a further alternative embodiment of direct viewing tube is illustrated in Figs. 6, 7, 8 and 9.

In Fig. 6 there is shown tube structure at 80, the gun portion of which may be identical with that described in connection with Fig. 3 and, therefore, is not illustrated in detail. The storage element 42 and the screen 43 may be identical also with those shown in Fig. 3. In this arrangement then the three or more color separation patterns may be impressed on the screen 41 in the same It is preferable however to arrange so that the scanned pattern will appear in a difierent arrangement on the screen so as to utilize more efl'iciently the surface of the screen. Thus the three images may be within the rectangles 84, 85 and 86 of Fig. 7. Instead of projecting these images onto separate unitary filter areas for the purpose of producing three color separation pictures, the separate electron images which appear to the right of screen 42 maybe focussed to a small area by means of electron lens elements 87, 88 and 89. These elements are shown in their approximate position in Fig. 7 but are diagrammatically shown displaced in Fig. 6 in order more clearly to illustrate the operation. By providing the proper voltages on the electrostatic elements, the three separate electron images may be focussed through openings 90, 91 and 92 respectively in a vertical wall 93 of an enclosure element 94 which also is provided with the proper voltage'to form part of the electrostatic lens system. Through these openings or apertures 90, 91, 92, the separate images Will be impressed through the mesh enclosure element 95 of element 94 so as to strike the phosphor coating 96 at different angles. Coating 96 constitutes mosaic of different color producing phosphors or different color filters behind a phosphor which produces white light. On the face of tube 80 in response to the electron streams of the seperate electron images, there will be presented a visible image made up of an intimate mixture of color spots of more or less brilliance depending upon the image signals. The color spots may be of a substantially true color picture.

This system utilizing the mesh screen and color focusscing mosaic is substantially the same system as has been previously proposed in connection with tri-color tube arrangements. However, the system differs considerably from that type of tube in that it does not produce the image in response to three guns whose beams are scanned over the mesh. The electron images passing through the apertures 90, 91 and 92 each comprise, in effect, a plurality of electron streams separately controlled by the storage screen which streams strike the openings in mesh 95 at different angles so that the electrons of the images will bombard the desired phosphor element; I t isclear that if the electrons coming through the openings 90, 91 and 92 are of sufficiently high velocity the dispersion caused by collision of the electrons within the enclosed volume will be relatively small due to the fact. that the actual electron concentration is relatively very slight. It is well known that the electrons will tend to travel in 1 straight lines and, therefore, most of theelectrons within 1 this enclosure will follow straight lines through to the various mesh apertures.

An understanding of the method by which the electrons are caused to strike different points on the phosphor screen may be clearer by reference to the diagrammatic disclosures of Figs. 8 and 9. 1

Turning first to Fig. 8, there are shown three separate planar sheets 97,98 and 99. It may be assumed that the spots 100, 101 and 102 on sheet 97 correspond to the openings 90, 91 and 920i Fig. 6, and that the single aperture 103 in sheet 98 corresponds to a single opening in the element 95. It will then be seen that electrons from spot 100 following the line 104 will impinge upon the surface of sheet 99 at point 105. V Electrons from spot 101 will travel along line'106 through aperture 103 and impinge, upon sheet 99 at point 107. Electrons from spot 102,will follow along line 108 and impinge upon sheet 99 at point 109. It will then be clear that the spots 105,

107 and 109 on sheet 99 may be made to correspond with the desired color elements by depositing the material at suitably spaced points. These spots will, of course, be

only of elemental totalarea.

Turning to Fig. 9, there isshown an element 110 whic may, correspond to the face of enclosure 94. directed toward the electron image guns and openings 111 and 112 which may correspond essentially to openings 91 and 92 as shown in Fig. 6. An element 113 is shown corresponding to screen.95 and on this element are shown three apertures 11 4, 115 and 116 corresponding to the three of the apertures in the meshscreen. It will be seen that electrons from aperturelll may follow three different 1 linear paths indicated at 117, 118 and 119 through the separated apertures 114, 115 and 116 so as to impinge upon corresponding phosphor elements indicated at 120, .121 and 122 which may be deposited on a glasselement 123., Similarly, the electrons from aperture 112 follow along paths 124, 125 and 126 through the respective apertures 114, 115, and116 and impinge upon the corresponding phosphors 127, 128 and 129. By making these phoshile this invention has been described 1 ence to line interlace, line interlac'e methods clearly may, be used withfthis system. In this case there W111 be,

of course, odd and .even lines in the. scanning picture so tliatfthe color switchingwillhave to take place in the proper order for that type of scanning. It.will then be evidentlthatfollowing through the successive scanning fieldsfwe may producea table somewhat as listed below:

i a .First field, red color, odd line .Second field, blue color, even line Third field, green color, odd line Fouth field, red color, even line Fifth field, blue color, odd line .JSiXth field, green color, even'line Thus thecolor images for the separate field's will be applied. so as to contact the desired elementinthe manner of interlace scanning in the .same way aspres'ently used injthe normal black and white transmission. 'It will however, be clear that because of the unique storimage's"may be produced either continuously entire screen or more rapidly than the writing beam will apply the separate signals so that a lower primary transmission rate may be used without detracting from the continuity of 'the picture or producing undesired flickering.

It will be clear that the specific embodiments illustrated are merely illustrations of applications of this invention and that many alternative structural arrangements will readily occur to those skilled in the art. The types of storage tube shown are not essential to the invention nor the particular type of reproduction means shown therein.

While the principles of this invention have been described above in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

:l. A system for reproducing energy signals representing a plurality of different aspects of the same signal pattern, comprising individual storage means for eachof said energy signals, means for successively applying signals representing said diiferent aspects to their respective storage means, means for continuously extracting information of said stored signals from all said storage means simultaneously with the application of said signals to any of said storage means and utilization means for effectively combining the difierent extracted components to reproduce said signal pattern.

1 2. A system according to claim 1, wherein said storage means comprise separate areas of a common storage screen.

3. A system according to claim 1, whereinsaid storage means comprise separate storage areas, and said means-for-successively-applying signals comprises separate signal applying electron beam sources directed toward said separate storage areas, means for scanning the beams from said sources over said areas, and means for successively rendering said sources eifective.

4. A system according to claim 3, wherein said continuously operative means comprises separate signal reading electron guns, and means for simultaneously scanning said signal reading guns over said areas.

5. A system according to claim 4, further comprising means for synchronizing the scanning of said reading electron guns with the scanning of each said electron signal applying guns.

6. A system for storing and reproducing energy signals representing a plurality of distinct but substantially identical scanned storage patterns comprising a plurality of storage surfaces, a first electron beam source, means for successively scanning an-electron beam from said source over said storage surfaces, means for applying the respective signal pattern to modulate energy of said first beam source during successive scansion of said surfaces to store energy representative of said patterns thereon, and a second electron beam source for simultaneously directing electron energy toward all said surfaces to reproduce signal responses corresponding to said stored energy.

7. A system according to claim 6, wherein said second electron beam source comprises a plurality of electron emitters corresponding to said storage surfaces and means for directing an electron beam from each of said emitters toward a corresponding storage surface.

8. A system according to claim 7, wherein said scanning means is positioned to scan each electron beam from said emitters over its corresponding surface during each successive scansion of the electron beam from said first source.

9. A system according to claim 8, further comprising individual collector electrodes for each of said storage surfaces, and separate output terminals coupled to each tures utilized in these tubes the various color; of said electrodes.

a,seo,1 1 1 '10. A system according to claim 9, wherein said storage surfaces comprise separate areas of a common dielectric surface.

11. A color television receiver for receiving signals representative of the different color fields, comprising a signal storage device, means for successively applying received signals to said storage device at a relatively low rate, means for extracting energy corresponding to said stored signals from said storage device a plurality of times between each storage period, and utilization means for said extracted energy.

12. A system for producing substantially flicker-free reproductions of a picture from picture signals representing different aspects of the same picture, transmitted at intervals sufficiently great normally to produce objectionable flicker upon reproduction, comprising electron beam responsive means for separately storing the energy representing said different aspects, and electron beam means for reproducing the original picture signals under infiuence of said stored energy at a rate substantially to avoid said flicker.

13. A system according to claim 12, wherein said electron beam means comprises means for reproducing said signals substantially continuously.

14. A system according to claim 12, wherein said electron beam means comprises separate electron beam guns for each said stored energies, and means for reproducing said signals for each aspect a plurality of times between each reception thereof.

15. A color television receiver for receiving signals representative of the different color fields, comprising a signal storage device, means for successively applying received signals to said storage device at a relatively low rate, means for extracting energy corresponding to said stored signals from said storage device substantially continuously during each storage period to produce separate electron images, means for producing visual images from said separate electron images, and means for superimposing said visual images.

16. A system for storing energy signals representing a plurality of different aspects of the same signal pattern, and reproducing a composite picture of said components, comprising a common storage screen having separate storage areas, means for successively applying signals of said different components to their respective storage areas, an electron source, continually operative means for simultaneously and continuously subjecting electrons from said source to the fields of said stored energies to modulate the flow of said electrons in accordance with information of said stored energies, means for producing images in response to said electrons, and means for effectively superimposing said images.

17. A system according to claim 16, wherein said means-for-suecessively-applying-signals comprises a first electron beam source and means for successively scanning a beam from said source over said separate areas.

18. A system according to claim 17, wherein said electron source comprises a flood electron source directed toward said screen.

19. A color television receiver for receiving signals representative of the different color fields, comprising a signal storage device, means for successively applying received signals to said storage device at a relatively low rate, electron means for extracting energy corresponding tosaid stored signals from said storage device substantially continuously during each storage period to control the number of electrons available from said electron means, means for producing separate visual reproduction images corresponding to said extracted energy, and means for effectively super-imposing said images.

20. An image reproduction system comprising a cathode ray tube having an electrostatic storage screen, means for establishing separate electrostatic charges over areas ofsaid screen corresponding with separate image signals, representing different characteristic aspects of a picture 12 image, reproduction means responsive to electron energy for producing effects of said different aspects, means for directing electrons to said reproduction means under control of respective of said separate charges, to produce said images in accordance with the separate image signals and means for effectively superimposing said images.

21. An image reproduction system, comprising a cathode ray tube, means for establishing electrostatic storage charges within said tube corresponding to the separate color fields of an image, a plurality of electron responsive means for reproducing the colors represented by said separate color fields, means within said tube for directing electrons to said responsive means under control of said established storage charges to produce images of varying color values corresponding to said color fields, and means for efiectively superimposing said produced images.

22. A color image reproducing system comprising a cathode ray tube, a perforate storage screen, a first electron beam source providing beams of elemental crosssection directed toward said screen, means for controlling said beams to direct them to relatively different points on said screen, means for successively scanning said beams over different areas of said screen about said different points, means for varying the intensity of said beams in accordance with different color information during the scanning over said difierent areas to impress corresponding electrostatic image charges on said areas, whereby a plurality of separate image control charge-areas are produced on said screen, a second electron beam source directed toward said screen, means for extending the area of coverage of electrons from said second source over the entire area of said screen, means for attracting electrons from said second source through the perforations of said screen to provide a plurality of electron images corresponding to said images charge on said screen, a plurality of color responsive means Within said tube corresponding to the colors of said color information, and means for focussing said electron images onto said color responsive areas.

23. In an electron beam image reproducing tube of the type in which separate image patterns may be produced on a storage screen and the stored image patterns may be used to control the effect of electrons from another source, a cathode ray gun assembly comprising a first electron beam forming device for producing beams of elemental cross section, an electron beam forming device in the path of the beams from said first device, said second device being provided with openings corresponding in number with said separate image patterns and said beams and control means for selectively releasing beam electrons of said first device through a selected of said openings.

24. An image reproduction system comprising a cathode ray tube having a perforate electrostatic storage screen, a first electron source for establishing separate electrostatic charges over areasof said screen corresponding with separate image signals representing diflferent characteristic components of a picture image, reproduction means responsive to electron energy for producing effects of said different components, a second electron source, means for directing electrons from said second source to said reproduction means under control of respective of said separate charges, to produce said images in accordance with the separate image signals and means for effectively superimposing said images.

25. A system according to claim 24 wherein said means for directing comprises means for attracting electrons from said second source through the perforations in said' screen.

26. A system according to claim 25, wherein said means for directing'further comprises an electrode having spaced openings of relatively small areas, mea'nsfor focussingthe' electrons attracted through said perforations to said openings, a mesh screen intermediate said openings and said reproduction means, and means for ferent respective discrete points.

27. An image reproduction system, comprising a cathode ray tube having a perforate electrostatic storage screen, a first electron source for establishing electrostatic storage charges corresponding to the separate color 'fields of an image upon said screen, a plurality of electron rcsponsive means for reproducing the colors represented by said separate color fields, a second electron source, means within said tube for directing electrons from said second source through the perforations of said storage screen to said responsive means under control of said established storage charges to produce images of varying color values corresponding to said color fields, and means for effectively superimposing said produced images.

28. A system according to' claim 27, wherein said 7 plurality of electron responsive means comprises color producing deposits covering separate discrete areas corresponding to the three color fields of said image.

29. A system according to claim 27, wherein said electron responsive means comprises a color responsive mosaichaving interspersed elemental size color responsive deposits, and said means-for-effective-superimposing comprises means for assuring registry of the electrons from the respective electron images.

30. A color image reproducingsystem comprising a cathode ray tube, a perforate storage screen, a cathode ray gun assembly comprising a first electron gun means for producing beams of elemental cross section directed toward said screen, a second gun in the path of the beams from said first gun, said second gun being provided with openings corresponding in number with said separate patterns and said first beams, control means for selectively controlling passages of the beams from said first gun means through a respective of said openings to impinge on different points of said screen, means for scanning the beams from said first gun over difierent areas of said screen about said difierent points, means for varying the intensity of said beams in accordance with diiferent color information during the scanning over said different areas to impress corresponding electrostatic image charges on said areas, whereby a plurality of separate image control charge-areas are produced on said screen, means for extending the area of coverage of electrons from said second gun over the entire area of said screen, means for attracting electrons from said second source through the perforations of said screen to provide a plurality of electron images corresponding to said stored images charge on said screen, a plurality of color responsive means within said tube corresponding to the colors of .said color information, and means for focussing said electron images onto respective of said color responsive means.

References, Cited in the file of this patent UNITED STATES PATENTS 2,273,172 Beers Feb. 17, 1942 2,587,005 Smith Feb. 26, 1952 2,587,006 Smith- Feb. 26, 1952 2,618,700 Weimer Nov. 18, 1952 2,621,244 Landon Dec. 9, 1952 2,634,327 Sziklai Apr. 7, 1953 

